99109 ÷ 8 = 12388 R5
Let's divide 99109 by 8.

Step 1:
8 goes into 9 1 times with a remainder of 1.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 8 from 9 to get 1.
Bring next digit (9) of the dividend behind the 1 and repeat the process: 19 / 8

Step 2:
8 goes into 19 2 times with a remainder of 3.
Write down 2 as next digit of of the result. 
Result so far: 12
Subtract 16 from 19 to get 3.
Bring next digit (1) of the dividend behind the 3 and repeat the process: 31 / 8

Step 3:
8 goes into 31 3 times with a remainder of 7.
Write down 3 as next digit of of the result. 
Result so far: 123
Subtract 24 from 31 to get 7.
Bring next digit (0) of the dividend behind the 7 and repeat the process: 70 / 8

Step 4:
8 goes into 70 8 times with a remainder of 6.
Write down 8 as next digit of of the result. 
Result so far: 1238
Subtract 64 from 70 to get 6.
Bring next digit (9) of the dividend behind the 6 and repeat the process: 69 / 8

Step 5:
8 goes into 69 8 times with a remainder of 5.
Write down 8 as next digit of of the result. 
Result so far: 12388
Subtract 64 from 69 to get 5.

The final result is 12388 with a remainder of 5.